feat: add durable store conformance harness

workplans/USER-WP-0016-durable-store-migration-and-conformance-harness.md

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+---
+id: USER-WP-0016
+type: workplan
+title: "Durable Store Migration And Conformance Harness"
+domain: netkingdom
+repo: user-engine
+status: finished
+owner: codex
+topic_slug: netkingdom
+planning_priority: medium
+planning_order: 16
+created: "2026-06-16"
+updated: "2026-06-16"
+depends_on:
+  - USER-WP-0009
+  - USER-WP-0015
+state_hub_workstream_id: "91f9494a-7cc8-4e61-bec8-9440dfe0e63d"
+---
+
+# USER-WP-0016 - Durable Store Migration And Conformance Harness
+
+## Goal
+
+Turn the durable-store follow-up from USER-WP-0009 into an executable adapter
+contract: ordered migrations, a Postgres bootstrap schema, and reusable
+conformance checks that future database-backed stores can run against the same
+behavior as the in-memory reference adapter.
+
+## Scope Direction
+
+This slice should stay inside user-engine and avoid production infrastructure
+dependencies. It should define what a provider-backed adapter must satisfy
+without requiring a live Postgres service in the local unit test suite.
+
+## Non-Goals
+
+- Do not add a production Postgres driver or connection lifecycle.
+- Do not own platform provisioning, credentials, backups, restores, or
+  provider observability.
+- Do not require Docker, a cloud database, or network access for the standard
+  test suite.
+
+## Tasks
+
+```task
+id: USER-WP-0016-T1
+status: done
+priority: high
+state_hub_task_id: "3783e912-76b5-4458-a8c5-a96bc8870e60"
+```
+
+Define an ordered migration manifest with the latest schema version and the
+logical store record types covered by user-engine.
+
+```task
+id: USER-WP-0016-T2
+status: done
+priority: high
+state_hub_task_id: "7d65e1fa-c7fb-4c83-9512-98296e6ccf4b"
+```
+
+Add a Postgres bootstrap SQL file that provider repositories can apply or
+translate when implementing the store boundary.
+
+```task
+id: USER-WP-0016-T3
+status: done
+priority: high
+state_hub_task_id: "c58db383-bfad-4f52-82d4-9d3c4558b1f2"
+```
+
+Add reusable store conformance helpers covering readiness, idempotent
+migration, core save/read methods, tenant and user queries, transaction
+rollback, outbox ordering, and redacted diagnostics.
+
+```task
+id: USER-WP-0016-T4
+status: done
+priority: medium
+state_hub_task_id: "71e51aa8-2a2b-463d-938b-0a1f1261c568"
+```
+
+Run the conformance helpers against `InMemoryUserEngineStore` as the reference
+implementation.
+
+```task
+id: USER-WP-0016-T5
+status: done
+priority: medium
+state_hub_task_id: "e8d7cece-605d-4bb3-b0c6-b03fb908e7c0"
+```
+
+Document how future Postgres/provider adapters should consume the manifest,
+SQL bootstrap file, and conformance harness.
+
+## Acceptance Criteria
+
+- `LATEST_SCHEMA_VERSION` and the local adapter schema version come from the
+  same manifest.
+- The Postgres bootstrap file contains durable tables for schema versions,
+  logical records, audit records, and outbox events.
+- A future adapter can import one conformance helper and run it with its own
+  store factory.
+- Standard local tests prove the harness against the in-memory store.
+- Diagnostics expose counts only and do not leak raw factor or profile values.
+
+## Expected Outputs
+
+- `user_engine.migrations` manifest.
+- `migrations/postgres/0001_user_engine_store.sql`.
+- `user_engine.testing.store_conformance` helper.
+- Store conformance tests.
+- Updated durable-store documentation.
+
+## Implementation Notes
+
+Implemented on 2026-06-16:
+
+- Added an ordered migration manifest with logical record and diagnostic count
+  keys.
+- Added a provider-facing Postgres bootstrap SQL file for the generic record,
+  audit, and outbox storage contract.
+- Added reusable store conformance helpers and reference tests for the
+  in-memory adapter.
+- Aligned local schema readiness with `LATEST_SCHEMA_VERSION`.
+- Documented the harness in the durable-store consumer requirements and
+  contracts docs.